RFR: 8308588: Unnecessary synchronized on GTKStyle#ICONS_MAP can be removed [v2]

[Alexey Ivanov]

On Fri, 30 Aug 2024 04:57:56 GMT, Abhishek Kumar <abhiscxk at openjdk.org> wrote:

>> `static final Map<String,GTKStockIcon> ICONS_MAP` is modified only in `static` block. Then [com.sun.java.swing.plaf.gtk.GTKStyle#get](https://github.com/kumarabhi006/jdk/blob/73f7a5f15dbba54a98f3916ff1190520ac07874d/src/java.desktop/share/classes/com/sun/java/swing/plaf/gtk/GTKStyle.java#L892) method read from it within `synchronized (ICONS_MAP)` block. As this map is read-only and all its content is initialized in static block we can safely remove synchronized from get call.
>
> Abhishek Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use Collections.unmodifiableMap and remove blank line

Marked as reviewed by aivanov (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/20741#pullrequestreview-2272702899